Blast attenuation seat

ABSTRACT

A seat for supporting an occupant of a vehicle and absorbing a force between the occupant and the vehicle created by relative movement between the occupant and the vehicle including a seat bottom and a seat back extending from the seat bottom. At least one of the seat bottom and the seat back includes a first energy absorbing device for absorbing at least a portion of the force when the force reaches a first magnitude. The one of the seat bottom and the seat back also includes a second energy absorbing device for absorbing at least a portion of the force when the force reaches a second magnitude greater than the first magnitude. The second energy absorbing device supports the first energy absorbing device so that the first energy absorbing device transmits a portion of the force to the second energy absorbing device when the force reaches the second magnitude.

CROSS-REFERENCE TO RELATED APPLICATIONS

The subject patent application claims priority to and all the benefitsof U.S. Provisional Patent Application No. 61/341,470, which was filedon Mar. 31, 2010, the entire specification of which is expresslyincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a seat for supporting an occupant of avehicle and absorbing a force between the occupant and the vehiclecreated by relative movement between the occupant and the vehicle

2. Description of the Related Art

Vehicles are widely used for military purposes, especially in recentmilitary conflicts, to transfer soldiers, to enter combat areas, topatrol areas, etc. Such vehicles can be exposed to blasts resulting froman explosive such as an improvised explosive device, a mine, a grenade,etc. Forces from such blasts are transferred through the vehicle to theoccupants. The vibration and/or reverberation of the blast through thevehicle can injure the occupants.

These vehicles can be armored to shield the occupants from such blastsbut the armor of the armored vehicle is designed to remain rigid duringa blast to deflect the blast and preserve the structural integrity ofthe vehicle, or at least the portion of the vehicle housing occupants.Unlike civilian automobiles that are designed to crush to absorb forcesresulting from an automobile crash, the armor on the armored vehicle,due to its rigidity, does not crush and thus does not absorb forcesresulting from the blast. As such, although the armor protects theoccupants by maintaining structural rigidity of the vehicle, the blastvibrates and/or reverberates through the vehicle because the armor doesnot deform to absorb the energy of the blast. This vibration and/orreverberation through the vehicle can injure the occupant. For example,if the blast originates below the vehicle, the blast can vibrate and/orreverberate through the floor of the vehicle. In such a scenario, theoccupant can be harmed if this vibration and/or reverberation istransferred directly to the occupant through the floor and/or the seat.

Further, whether the vehicle is armored or not, much of the technologyfor absorbing energy in a civilian automobile during an automobileaccident is not suitable for absorbing energy from an explosive blast.As one example, conventional civilian automobiles are equipped withairbags that inflate upon crash of the automobile. The airbag caninflate within 5 milliseconds. Due to the speeds of typical civilianautomobile accidents and/or due to the crushing of the automobile toabsorb energy, the immediate need for inflation of the airbag is notnecessary and the 5 millisecond delay is acceptable. In other words, ina civilian automobile accident, the inflation of the airbag is notneeded earlier than 5 milliseconds after the crash. However, in the caseof an explosive blast, the magnitude of the blast can be such that theforces of the blast are almost instantaneously transferred to theoccupant, i.e., forces that can harm the occupant are transferredthrough the armored vehicle in less than 5 milliseconds. Further, in thecase of an armored vehicle, for example, the armor is relatively rigidand does not absorb much, if any, forces. As such, much or all of theforce resulting from the blast is transferred virtually instantaneouslythrough the vehicle to the occupant. As such, the airbags used incivilian automobiles cannot react quickly enough due to the 5millisecond delay associated with the civilian automobile airbags.

In addition to generating initial forces acting on the vehicle, theblast can also cause the vehicle to become airborne. The occupant cansuffer injuries relating to the landing of the vehicle on the ground,i.e., the “slam down.”

SUMMARY OF THE INVENTION AND ADVANTAGES

The present invention includes a seat for supporting an occupant of avehicle and absorbing a force between the occupant and the vehiclecreated by relative movement between the occupant and the vehicle. Theseat comprises a seat bottom and a seat back extending from the seatbottom. At least one of the seat bottom and the seat back includes afirst energy absorbing device for absorbing at least a portion of theforce when the force reaches a first magnitude. The one of the seatbottom and the seat back includes a second energy absorbing device forabsorbing at least a portion of the force when the force reaches asecond magnitude greater than the first magnitude. The second energyabsorbing device supports the first energy absorbing device so that thefirst energy absorbing device transmits a portion of the force to thesecond energy absorbing device when the force reaches the secondmagnitude.

The first and second energy absorbing devices increase the overall rangeof forces that can be absorbed by the seat. In other words, the firstenergy absorbing device absorbs forces that are lower than forcesabsorbed by the second energy absorbing device and the second energyabsorbing device absorbs forces that are higher than forces absorbed bythe first energy absorbing device. Because the second energy absorbingdevice supports the first energy absorbing device, the second energyabsorbing device absorbs at least a portion of the force when the firstenergy absorbing device ceases to absorb the force. In addition, thefirst and second energy absorbing devices can be individually tuned orsized to increase the range of forces absorbed by the seat.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a vehicle partially cut away to show aseat in the vehicle;

FIG. 2 is a front perspective view of a portion of the seat;

FIG. 3 is a partially exploded view of a portion of the seat;

FIG. 4 is a rear perspective view of a portion of the seat;

FIG. 5A is a side view of a third energy absorbing device of the seatwhen no force or a force less than a third magnitude is applied to theseat;

FIG. 5B is a side view of the third energy absorbing device when a forceon the seat exceeds the third magnitude;

FIG. 6 is a sectional and partial cut-away view of the seat when a forceof a first magnitude is applied to the seat;

FIG. 7 is a sectional and partial cut-away view of the seat when a forceof a second magnitude is applied to the seat;

FIG. 8 is a sectional and partial cut-away view of the seat when a forceof the third magnitude is applied to the seat;

FIG. 9 is a partially exploded view of a seat of a second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate like partsthroughout the several views, a blast attenuation seat is showngenerally at 10 and is referred to hereinafter as “the seat 10.” Asshown in FIG. 1, the seat 10 is mounted in a vehicle 12 for supportingan occupant (not shown).

The seat 10 is typically mounted in a military vehicle but can also bemounted in a non-military vehicle such as, for example, a lawenforcement vehicle or a civilian vehicle. Whether the vehicle 12 is amilitary vehicle or otherwise, the vehicle 12 can be a land vehicle suchas, for example, an automobile, a tank, a bus, a train, etc.; a watervehicle such as, for example, a boat or a submarine; or an air vehiclesuch as, for example, an airplane or helicopter. Typical military usesof the seat 10 include, for example, armored vehicles and tanks.

The seat 10 supports the occupant of the vehicle 12 and absorbs a forcebetween the occupant and the vehicle 12 created by relative movementbetween the occupant and the vehicle 12. Specifically, the seat 10absorbs the force transmitted through the vehicle 12 to the seat 10 froma blast that originates exterior to the vehicle 12 in order to minimizeforce exerted through the seat 10 to the occupant. The blast can becaused by, for example, an explosive such as an improvised explosivedevice, a mine, a grenade, etc. The blast can result from an explosivein or on the ground or in the air around the vehicle 12. As one example,the blast can result from the vehicle 12 moving over a buried explosive.As set forth further below, the blast can also cause the vehicle 12 tobecome airborne and/or flip sideways, forward, and/or rearward, in whichcase the seat 10 not only absorbs the force resulting from the initialblast but also absorbs additional forces resulting from the impact ofthe vehicle 12 on the ground. In any event, regardless of the locationof the explosive and the effect of the explosive on the vehicle 12, theseat 10 absorbs the force transmitted through the vehicle 12 to the seat10.

With reference to FIGS. 2-4, the seat 10 includes a seat bottom 14 and aseat back 16 extending upwardly from the seat bottom 14. The seat back16 includes a seat back frame 18 and the seat bottom 14 includes a seatbottom frame 20. Typically, the seat back frame 18 and the seat bottomframe 20 are formed of metal; however, it should be appreciated that theseat back frame 18 and the seat bottom frame 20 can be formed of anysuitable material to provide proper support 42 for the occupant.

With reference again to FIG. 1, the seat back 16 can include a seat backcushion 22 mounted to the seat back frame 18 and the seat bottom 14 caninclude a seat bottom cushion 24 mounted to the seat bottom frame 20.The seat back cushion 22 and seat bottom cushion 24 are only partiallyshown in FIG. 1 and are not shown in FIGS. 2-4 and 6-9 for illustrativepurposes. Specifically, the seat back cushion 22 and the seat bottomcushion 24 typically include foam (not shown) covered by fabric (notshown). The foam and fabric typically cover the seat back frame 18 andthe seat bottom frame 20. The foam and the fabric of the seat backcushion 22 can be the same type of material or a different type ofmaterial than the foam and the fabric of the seat bottom cushion 24.When the force is exerted by the blast through the vehicle 12 to theseat 10, the foam compresses between the occupant and the seat bottomframe 20 and/or the seat back frame 18 to absorb at least a portion ofthe force to reduce or eliminate the magnitude of the force delivered tothe occupant. The foam is typically resilient such that the foam returnsto a pre-blast configuration after absorbing the force from the blast.

With reference again to FIGS. 2-4, the seat bottom 14 includes a firstenergy absorbing device 26, a second energy absorbing device 28, and athird energy absorbing device 30. As set forth further below, the first26, second 28, and/or third 30 energy absorbing devices allow movementof at least one of the seat bottom 14 and the seat back 16 relative tothe vehicle 12 in response to the force of the blast and absorb at leasta portion of the force. The first 26, second 28, and third 30 energyabsorbing devices are active, i.e., instantaneously respond to force.The seat 10 is tunable in that the first 26, second 28, and third 30energy absorbing devices can each be designed so that, in combination,the first 26, second 28, and third 30 energy absorbing devices canabsorb energy over a large range of forces.

At least one of the seat bottom 14 and the seat back 16 includes thefirst energy absorbing device 26 for absorbing at least a portion of theforce of the blast when a magnitude of the force reaches a firstmagnitude F1. As shown in the FIGS. 2-4, both the seat bottom 14 and theseat back 16 include first energy absorbing devices 26. The first energyabsorbing device 26 of the seat back 16 and the seat bottom 14 istypically disposed beneath the seat back cushion 22 and the seat bottomcushion 24, respectively. In other words, the foam and fabric of theseat back cushion 22 and the seat bottom cushion 24 covers the firstenergy absorbing device of the seat bottom 14 and the seat back 16,respectively. As set forth above, the foam and fabric of the seat backcushion 22 and the seat bottom cushion 24 is not shown in the Figures inorder to show the other features of the seat 10.

At least one of the seat bottom 14 and the seat back 16 also typicallyincludes the second energy absorbing device 28 for absorbing at least aportion of the force of the blast when a magnitude of the force reachesa second magnitude F2 greater than the first magnitude F1 and a thirdenergy absorbing device 30 for absorbing for absorbing at least aportion of the force when a magnitude of the force exceeds a thirdmagnitude F3 greater than the second magnitude F2. As shown in FIGS.2-4, the seat bottom 14 includes the second energy absorbing device 28and the third energy absorbing device 30. It should be appreciated thatthe, while not shown in the Figures, the seat back 16 can include thesecond 28 and third 30 energy absorbing devices.

FIGS. 6-8 show the seat 10 reacting to the forces of the first magnitudeF1, second magnitude F2, and third magnitude F3, respectively. The first26, second 28, and third 30 energy absorbing devices can be designedsuch that the first magnitude F1, the second magnitude F2, and the thirdmagnitude F3 can have any numerical measurement or range of numericalmeasurements. For example, the first magnitude F1 of the force, i.e.,the magnitude that activates the first energy absorbing device 26, istypically between 15 and 100 G. The second magnitude F2 of the force,i.e., the magnitude that activates the second energy absorbing device28, is typically 100 and 300 G. The third magnitude F3 of the force,i.e., the magnitude that activates the third energy absorbing device 30,typically has a magnitude of between 300 and 550 G.

The first 26, second 28, and third 30 energy absorbing devices arearranged to function in series. In other words, the first 26, second 28,and third 30 energy absorbing devices 30 each respectively absorbprogressively larger forces. Said differently, if the force exceeds therange of the first energy absorbing device 26, the first energyabsorbing device 26 absorbs a portion of the force and transfers aportion of the force to the second energy absorbing device 28 Likewise,if the force exceeds the range of the second energy absorbing device 28,the first 26 and second 28 energy absorbing devices absorb a portion ofthe force and the second energy absorbing device 28 transfers a portionof the force to the third energy absorbing device 30.

The first energy absorbing device 26 is configured to absorb at least aportion of the force when the force reaches the first magnitude F1,i.e., during a blast, the first energy absorbing device 26 is activatedand absorbs at least a portion of the force when the force reaches thefirst magnitude F1. If, on the other hand, the force is smaller than thefirst magnitude F1, then the first energy absorbing device 26 remainsdeactivated and does not absorb any of the force. The first energyabsorbing device 26 can be loaded to a completely loaded state, in whichstate the first energy absorbing device 26 does not absorb additionalforce. Typically, the first energy absorbing device 26 reaches the fullyloaded state at a magnitude of the force at least as high as the secondmagnitude F2.

The second energy absorbing device 28 is configured to absorb at least aportion of the force when the magnitude of the force reaches the secondmagnitude F2. If the force exceeds the second magnitude F2 and the firstenergy absorbing device 26 reaches the completely loaded state, thesecond energy absorbing device 28 is activated and, in addition to theactivation of the first energy absorbing device 26, absorbs at least aportion of the force. If, on the other hand, the force remains smallerthan the second magnitude F2, then the second energy absorbing device 28remains deactivated and does not absorb any of the force. The secondenergy absorbing device 28 can be loaded to a completely loaded state,in which state the second energy absorbing device 28 does not absorbadditional force. Typically, the second energy absorbing device 28reaches the fully loaded state at a magnitude of the force at least ashigh as the third magnitude F3.

The third energy absorbing device 30 is configured to absorb at least aportion of the force when the force reaches the third magnitude F3. Ifthe force exceeds the third magnitude F3 and the second energy absorbingdevice 28 reaches the completely loaded state, the third energyabsorbing device 30 is activated and, in addition to the activation ofthe first 26 and second 28 energy absorbing devices, absorbs at least aportion of the force. If, on the other hand, the force remains smallerthan the third magnitude F3, then the third energy absorbing device 30remains deactivated and does not absorb any of the force.

With reference to FIGS. 2-4, the first energy absorbing device 26includes a frame, such as the seat bottom frame 20 or the seat backframe 18, and a pan 32 spaced from the frame 18, 20. The pan 32 istypically connected to the frame 18, 20 with at least two links 34 thatare each pivotally connected to the frame 18, 20 and the pan 32.Alternatively, the pan 32 can be moveably connected to the frame 18, 20in any suitable fashion.

With reference to FIG. 4, a first resilient member 36 is disposedbetween the frame 18, 20 and the pan 32 to urge the pan 32 away from theframe 18, 20. Specifically, any number of first resilient members 36 canbe disposed between the frame 18, 20 and the pan 32. The first resilientmember 36 can be, for example, a torsion spring, a coil spring, ahydraulic damper, a pneumatic damper, etc.

With reference to FIG. 6, the first resilient member 36 is designed tomaintain the pan 32 in position relative to the frame 18, 20 until theforce reaches the first magnitude F1. In other words, in the absence ofa force of the first magnitude F1, e.g., from a blast, the pan 32 doesnot move to support 42 the occupant without loading the first resilientmember 36, as shown in phantom lines in FIG. 6. When the force reachesor exceeds the first magnitude F1, the force overcomes the firstresilient member 36 and begins to load the first resilient member 36. Asthe force overcomes the first resilient member 36, the pan 32 movesrelative to the frame 18, 20, as shown in solid lines in FIG. 6.

The first energy absorbing device 26 resiliently moves when absorbing atleast a portion of the force. As such, as the force resides, the firstenergy absorbing device 26 returns to a pre-force position. In otherwords, the pan 32 and the first resilient member 36 return to a positionthat the pan 32 and the first resilient member 36 had before the forcewas applied, i.e., the position shown in phantom lines in FIG. 6.

With reference again to FIGS. 2-4, the second energy absorbing device 28includes a linkage 38 and a second resilient member 40 operativelycoupled to the linkage 38. The second resilient member 40 can be, forexample, a shock absorber including a cylinder and a pistontelescopically received in the cylinder. Such a shock absorber can be,for example, hydraulically or pneumatically operated. It should beappreciated that the second resilient member 40 can be of any suitabletype without departing from the nature of the present invention.

A support 42 is spaced from the seat bottom frame 20 and the secondenergy absorbing device 28 is coupled to the seat bottom frame 20 andthe support 42. Specifically, the linkage 38 is coupled to the frame 18,20 and the support 42 and a second resilient member 40 is operativelycoupled to the linkage 38. The seat 10 can include any number of secondenergy absorbing devices 28. For example, as shown in FIGS. 2-4, theseat 10 has two second energy absorbing devices 28.

With reference to FIG. 7, the linkage 38 includes a first pair of links44 and a second pair of links 46 with the second resilient member 40extending between the first pair of links 44 and the second pair oflinks 46. Each of the first 44 and second 46 pair of links includes anupper link 48 pivotally coupled to the seat bottom frame 20 and a lowerlink 50 pivotally coupled to the support 42. The upper 48 and lower 50links of the first pair of links 44 are pivotally coupled to each otherat a joint 52 and the upper 48 and lower 50 links of the second pair oflinks 46 are pivotally coupled to each other at a joint 54.

The linkages 38 of the two second energy absorbing devices 28 can beconnected to each other such that the second energy absorbing devices 28are arranged in parallel, as shown in the Figures, or in series (notshown). For example, the seat 10 can include upper cross members 56 thatconnect the upper links 48 of the second energy absorbing members 28together and lower cross members 58 that connect the lower links 50 ofthe second energy absorbing members 28 together, as shown in FIGS. 2-4.

The upper cross members 56 and lower cross members 58 interconnect thetwo second energy absorbing devices 28 to the seat bottom frame 20 andthe support 42 so that that the second energy absorbing devices 28 worktogether in a balanced fashion. This arrangement prevents twisting ofthe seat 10 when the second energy absorbing devices 28 are loaded.

The upper cross members 56 extend from the upper links 48 to the seatbottom frame 20 to couple the upper links 48 with the seat bottom frame20. The upper cross members 56 typically extend through the upper links48 and through the seat bottom frame 20 and each upper cross member 56is pivotally coupled to at least one of the upper link 48 and the seatbottom frame 20. The lower cross members 58 extend from the lower link50 to the support 42 to couple the lower link 50 to the support 42. Thelower cross members 58 typically extend through the lower link 50 andthrough the support 42 and each lower cross member 58 is pivotallycoupled to at least one of the lower link 50 and the support 42.

The second resilient member 40 is connected to and extends between thefirst and second pairs of links 34. Typically, the second resilientmember 40 extends from the joint 52 of the first pair of links 44 to thejoint 54 of the second pair of links 46. Alternatively, the secondresilient member 40 can be connected to the upper link 48 or the lowerlink 50 of the first and/or second pairs of links 34.

The second resilient member 40 is designed to maintain the seat bottomframe 20 in position relative to the support 42 until the force reachesthe second magnitude F2. In other words, in the absence of a force of asecond magnitude F2, e.g., from a blast, the seat bottom frame 20 doesnot move and supports the occupant without loading the second resilientmembers 40, as shown in FIG. 6. As shown in FIG. 7, when the forcereaches or exceeds the second magnitude F2, the force overcomes thesecond resilient members 40 and begins to load the second resilientmembers 40. As the force overcomes the second resilient member 40, theseat bottom frame 20 moves relative to the support 42.

During a blast, force is transmitted through the seat 10 to the firstand second pair of links 46. This force urges the upper 48 and lower 50links to pivot about the joints, respectively. The second energyabsorbing device 28 is configured such that, if a force of the secondmagnitude F2 is applied to the seat 10, the force on the upper 48 andlower 50 links overcome the second resilient member 40 such that theupper 48 and lower 50 links pivot about the joints 52, 54, respectively.In other words, the upper 48 and lower 50 links move in a scissor-likemotion. The blast causes the first 44 and second 46 pair of links topull the second energy absorbing device 28 in tension.

The second energy absorbing device 28 resiliently moves when absorbingat least a portion of the force. As such, as the force resides, thesecond energy absorbing device 28 returns to a pre-force position. Inother words, the seat bottom frame 20 returns to a position that theseat bottom frame 20 had before the force was applied, i.e., as shown inFIG. 6.

The second energy absorbing device 28 extends between the first energyabsorbing device 26 and the third energy absorbing device 30. The secondenergy absorbing device 28 supports the first energy absorbing device26. Specifically, the second energy absorbing device 28 supports theseat bottom frame 20 so that the first energy absorbing device 26transmits a portion of the force to the second energy absorbing device28 when the force exceeds the first magnitude F1. In other words, thesecond energy absorbing device 28 acts as a foundation for the firstenergy absorbing device 26. As set forth above, when the magnitude ofthe force is less than the second magnitude F2, the second energyabsorbing device 28 remains deactivated and the seat bottom frame 20maintains position relative to the support 42, as shown in FIG. 6. Ifthe magnitude of the force loads the first energy absorbing device 26 tothe fully loaded state, i.e., a force greater than the second magnitudeF2, the first energy absorbing device 26 is unable to absorb additionalforce and instead transmits additional force to the second energyabsorbing device 28.

With reference again to FIGS. 2-4, the seat 10 includes a base 60 forconnecting to the vehicle 12. The base 60 is mounted to the vehicle 12,and particularly, for example, to a floor 62 of the vehicle 12.Alternatively or in addition, the base 60 can be mounted to another partof the vehicle 12 such as, for example, an interior side of the vehicle12.

With reference to FIG. 8, the third energy absorbing device 30 includesa cup 64 attached to one of the base 60 and the support 42 and a rod 66attached to the other of the base 60 and the support 42. For example, asshown in FIG. 8, the cup 64 is connected to the support 42 and the rod66 extends from the base 60 upwardly into the cup 64. The cup 64includes an interior wall 68 that defines a cavity 70 receiving the rod66. The rod 66 abuts the interior wall 68. The interior wall 68 caninclude protrusions 72 that extend into the cavity 70 and abut the rod66. The rod 66 tapers from the base 60 toward the protrusions 72.

The third energy absorbing device 30 is designed to maintain the support42 in position relative to the base 60 until the force reaches the thirdmagnitude F3. In other words, in the absence of a force of the thirdmagnitude F3, e.g., from a blast, the support 42 does not move andsupports the occupant, as shown in FIG. 7. The relative position of therod 66 and the cup 64 of FIG. 7 is shown in greater detail in FIG. 5A.When the force reaches or exceeds the third magnitude F3, the forceovercomes the third energy absorbing device 30. As the force overcomesthe third energy absorbing device 30, the support 42 moves toward thebase 60 as shown in FIG. 8. The relative position of the rod 66 and thecup 64 of FIG. 8 is shown in greater detail in FIG. 5B.

Specifically, when the force reaches the third magnitude F3, the rod 66is forced deeper into the cavity 70 and the rod 66 and/or theprotrusions 72 plastically deform to absorb at least a portion of theforce, as shown in FIG. 5B and FIG. 8. After the blast, the third energyabsorbing device 30 is typically replaced since the rod 66 and/or theprotrusions 72 are plastically deformed.

The rod 66 and the cup 64 are typically formed of steel. Alternatively,the rod 66 and cup 64 can be formed of any type of material suitable fordeform to absorb energy.

The third energy absorbing device 30 extends between the base 60 and thesecond energy absorbing device 28. The third energy absorbing device 30supports the second energy absorbing device 28. Specifically, the thirdenergy absorbing device 30 supports the support 42 so that the secondenergy absorbing device 28 transmits a portion of the force to the thirdenergy absorbing device 30 when the force exceeds the second magnitudeF2. In other words, the third energy absorbing device 30 acts as afoundation for the second energy absorbing device 28. As set forthabove, when the magnitude of the force is less than the third magnitudeF3, the third energy absorbing device 30 remains stationary and thesupport 42 maintains position relative to the base 60, as shown in FIG.7. If the magnitude of the force loads the second energy absorbingdevice 28 to the fully loaded state, i.e., a force greater than thethird magnitude F3, the second energy absorbing device 28 is unable toabsorb additional force and instead transmits additional force to thethird energy absorbing device 30.

The base 60 is typically mechanically fastened to the vehicle 12 withmechanical fasteners (not shown) such as, for example, threaded bolts sothat the base 60 can be easily replaced by merely unfastening themechanical fasteners. The base 60 defines a track 74 and the thirdenergy absorbing device 30, e.g., the rod 66, is slideably disposed inthe track 74. As such, a position of the seat 10 can be adjusted alongthe base 60.

With reference again to FIGS. 2-4, the seat 10 can include one or morebases 60 and one or more third energy absorbing devices 30. For example,in FIGS. 2-4, the seat 10 includes two bases 60 and four third energyabsorbing devices 30. Two third energy absorbing devices 30 are mountedto each base 60. In such a configuration, the multiple third energyabsorbing devices 30 evenly distribute the force to the second 28 andfirst 26 energy absorbing devices.

The bases support 42 the rest of the seat 10 in the vehicle 12 such thatthe seat 10 is modular, i.e., self contained. The entire seat 10 can beinstalled into or removed from the vehicle 12 by merely disconnectingthe bases 60 from the vehicle 12. This modular arrangement also allowsfor one or more seats 10 to be easily installed in various seatingconfigurations in the vehicle 12. In addition, the seat 10 can be easilyremoved from the vehicle 12 for replacement or service.

As set forth above, the blast may cause the vehicle 12 to becomeairborne, which results in an event called a “slam down” when thevehicle 12 lands. As shown in FIG. 2, the seat 10 can include aninflatable device 76 such as, for example, an airbag to cushion theoccupant on the slam down. In other words, the inflatable device 76increases the “ride down time.” As set forth above, the first 26 andsecond 28 energy absorbing devices are resilient and, as such, the first26 and second 28 energy absorbing devices can reset before the slamdown. The inflatable device 76 can aid the reset first 26 and second 28energy absorbing devices on slam down. The inflatable device 76 can alsoprovide the primary energy absorption in the event that the first and/orsecond energy absorbing device 28 do not reset before the slam down.

The inflatable device 76 can be, for example, disposed on the pan 32 ofthe seat bottom 14 and/or the seat back 16 and is configured toselectively inflate for cushioning between the occupant and the pan 32.The inflatable device 76 is configured to inflate when the vehicle 12 isairborne so that the inflatable device 76 can immediately absorb energywhen the vehicle 12 lands. The inflatable device 76 can also bepositioned on the pan 32 to prevent “submarining” of the occupant asdiscussed further below. The inflatable device 76 includes a bag that istypically formed of a shrapnel-resistant material such as, for example,Nomex and/or Kevlar.

The inflatable device 76 can include, for example, a computer (notshown) having a sensor for sensing the blast and inflating theinflatable device 76. The computer can be programmed such that, forexample, the inflation of the inflatable device 76 can be delayed sothat the inflatable device 76 does not interfere with the energyabsorption of the first 26, second 28, and third 30 energy absorbingdevices. After the initial delay, the inflatable device 76 is inflatedbefore the vehicle 12 lands. For example, the computer can be programmedsuch that the airbag inflates 25-150 milliseconds after the blast.

Alternatively, the computer can calculate the proper inflation delaybased on the details of the blast. In such a configuration, theinflatable device 76 includes sensors (not shown) for measuringcharacteristics such as location and magnitude of the blast. Based onthese measurements, the computer calculates the effect of the blast onthe vehicle 12 and instructs the airbag to inflate at a time when thevehicle 12 is calculated to be in the air.

With reference to FIGS. 2 and 3, the seat 10 can include a footrest 78connected to the base 60 for supporting the feet of the occupant spacedfrom the floor 62 of the vehicle 12. The footrest 78 isolates theoccupant from the floor 62 of the vehicle 12. Such a configurationprevents force from being transferred from the floor 62 of the vehicle12 to the feet of the occupant.

With reference to FIG. 1, the seat 10 can include a seatbelt 80. FIG. 1shows a five-point seatbelt for exemplary purposes, but the seatbelt 80can be of any kind, such as, for example, a three-point seatbelt,without departing from the nature of the present invention. The seatbelt80 is self-contained on the seat 10. In other words, the seatbelt 80 isanchored to the seat 10, e.g., the seat back frame 18 and/or the seatbottom frame 20 thereby eliminating the need for anchoring the seatbelt80 to the vehicle body or floor 62. As such, as set forth above, theentire seat 10 can be installed into or removed from the vehicle 12 bymerely disconnecting the base 60 from the vehicle 12, i.e., without theneed for disconnecting the seatbelt 80 from the vehicle 12, so that theseat 10 is modular.

An anti-submarine feature 82 can be coupled to the seat bottom frame 20to provide resistance to “submarining” of the occupant during a blast,i.e., to prevent the occupant from moving forward on the seat bottom 14and sliding underneath the seatbelt 80. The anti-submarine featuretypically includes a thigh support 42 pivotally coupled to the seatbottom frame 20. In a scenario where the blast causes the occupant tomove forward and/or downwardly in the seat 10, force applied to thethigh support 42 by thighs of the occupant causes the thigh support 42to rotate to prevent further forward movement of the occupant.

FIGS. 1-8 show a first embodiment of the seat 10 and FIG. 9 shows asecond embodiment of the seat 110. Features of the second embodimentthat are similar to features of the first embodiment are identified withthe reference numeral of the first embodiment preceded by a “1.” In thesecond embodiment, the seat bottom 114 and the seat back 116 eachinclude a plurality of pans 132. The pans 132 are rotated and/ortranslated when the first energy absorbing device 26 is activated. Theseat 10 of the second embodiment also includes an active head restraint84. The active head restraint 84 is typically pivotally coupled to theseat back frame 18. In the scenario where the occupant is pushed backinto the seat 10, e.g., during a blast, the active head restraint 84pivots forwardly toward the head of the occupant to reduce the whiplashof the occupant.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation. Manymodifications and variations of the present invention are possible inlight of the above teachings, and the invention may be practicedotherwise than as specifically described.

1. A seat for supporting an occupant of a vehicle and absorbing a force between the occupant and the vehicle created by relative movement between the occupant and the vehicle, said seat comprising: a seat bottom; and a seat back extending from said seat bottom; at least one of said seat bottom and said seat back including a first energy absorbing device configured to absorb at least a portion of the force when a magnitude of the force reaches a first magnitude; said one of said seat bottom and said seat back including a second energy absorbing device configured to absorb at least a portion of the force when the magnitude of the force reaches a second magnitude greater than the first magnitude; and said second energy absorbing device supporting said first energy absorbing device so that said first energy absorbing device transmits a portion of the force to said second energy absorbing device when the magnitude of the force reaches the second magnitude.
 2. The seat as set forth in claim 1 further comprising a third energy absorbing device configured to absorb at least a portion of the force when the force reaches the third magnitude.
 3. The seat as set forth in claim 2 further comprising a base for connecting to the vehicle with said third energy absorbing device supporting said second energy absorbing device on said base.
 4. The seat as set forth in claim 3 wherein said third energy absorbing device extends between said base and said second energy absorbing device and wherein said second energy absorbing device extends between said third energy absorbing device and said first energy absorbing device.
 5. The seat as set forth in claim 2 wherein said second energy absorbing device extends between said first energy absorbing device and said third energy absorbing device.
 6. The seat as set forth in claim 2 wherein said third energy absorbing device supports said second energy absorbing device so that said second energy absorbing device transmits a portion of the force to said third energy absorbing device when the force reaches the third magnitude.
 7. The seat as set forth in claim 2 wherein said third energy absorbing device is configured to plastically deform to absorb at least a portion of the force when the force exceeds the third magnitude.
 8. The seat as set forth in claim 7 wherein said first energy absorbing device and said second energy absorbing device each resiliently move when absorbing at least a portion of the force.
 9. The seat as set forth in claim 1 wherein said first energy absorbing device includes a frame and a pan with a first resilient member disposed between said frame and said pan.
 10. The seat as set forth in claim 9 further comprising a support spaced from said frame with said second energy absorbing device coupled to said frame and said support.
 11. The seat as set forth in claim 10 wherein said second energy absorbing device includes a linkage coupled to said frame and said support and a second resilient member operatively coupled to said linkage.
 12. The seat as set forth in claim 10 further comprising a base for connection to the vehicle and a third energy absorbing device supporting said support on said base.
 13. The seat as set forth in claim 12 wherein said third energy absorbing device is configured to absorb at least a portion of the force when the force reaches a third magnitude greater than the second magnitude.
 14. The seat as set forth in claim 12 wherein said third energy absorbing device extends from said base to said support and wherein said second energy absorbing device extends from said support to said frame.
 15. The seat as set forth in claim 9 further comprising an inflatable device disposed on said pan and configured to selectively inflate for cushioning between the occupant and said pan.
 16. A seat for supporting an occupant of a vehicle and absorbing a force between the occupant and the vehicle created by relative movement between the occupant and the vehicle, said seat comprising: a seat bottom; and a seat back extending from said seat bottom; at least one of said seat bottom and said seat back including a first energy absorbing device for absorbing at least a portion of the force when the force reaches a first magnitude; said one of said seat bottom and said seat back including a second energy absorbing device for absorbing at least a portion of the force when the force reaches a second magnitude greater than the first magnitude; and said second energy absorbing device supporting said first energy absorbing device so that said first energy absorbing device transmits a portion of the force to said second energy absorbing device when the force reaches the second magnitude.
 17. The seat as set forth in claim 16 further comprising a third energy absorbing device supporting said second energy absorbing device for absorbing a portion of the force from the second energy absorbing device when the force reaches a third magnitude greater than the second magnitude.
 18. The seat as set forth in claim 16 wherein said first energy absorbing device includes a frame and a pan with a first resilient member disposed between said frame and said pan.
 19. The seat as set forth in claim 18 further comprising a support spaced from said frame with said second energy absorbing device coupled to said frame and said support.
 20. The seat as set forth in claim 19 further comprising a third energy absorbing device supporting said second energy absorbing device and a base for connection to the vehicle with the third energy absorbing device supporting said support on said base. 